# MIT License # Copyright (c) 2017-2020 Guy Carpenter # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # The above copyright notice and this permission notice shall be included in all # copies or substantial portions of the Software. # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE. from time import sleep_ms from machine import I2C, Pin class LCD: def __init__(self, addr, cols, rows, i2c): self.addr = addr self.cols = cols self.rows = rows self.i2c = i2c self.backlight = True self.displayfunction = 0 self.displaycontrol = 0 self.displaymode = 0 self.init_display() def _write_byte(self, value, char_rs): """ Send byte to data pins char_rs=1 Data / command=0 """ self.i2c.writeto(self.addr, bytes([(value >> 4) | char_rs | (self.backlight << 3) | 0x4, (value >> 4) | char_rs | (self.backlight << 3) | 0x6, (value >> 4) | char_rs | (self.backlight << 3) | 0x2, (value >> 4) | char_rs | (self.backlight << 3)])) self.i2c.writeto(self.addr, bytes([((value & 0x0F) << 4) | char_rs | (self.backlight << 3) | 0x4, ((value & 0x0F) << 4) | char_rs | (self.backlight << 3) | 0x6, ((value & 0x0F) << 4) | char_rs | (self.backlight << 3) | 0x2, ((value & 0x0F) << 4) | char_rs | (self.backlight << 3)])) sleep_ms(1) def _command(self, value): """ Send command to LCD """ self._write_byte(value, 0) def _data(self, value): """ Send data to LCD """ self._write_byte(value, 1) def init_display(self): """ Initialise display """ self.displayfunction = 0x20 | 0x04 # 4-bit mode, 2 lines, 5x8 dots self._command(0x33) self._command(0x32) self._command(self.displayfunction) self.displaycontrol = 0x08 | 0x04 | 0x00 # Display on, cursor on, blink off self._command(self.displaycontrol) self.clear() self.displaymode = 0x04 | 0x02 # Entry left, shift cursor self._command(self.displaymode) sleep_ms(200) def clear(self): """ Clear display, set cursor to home """ self._command(0x01) sleep_ms(2) def set_cursor(self, row, col): """ Set cursor to specified row and column (0-indexed) """ if row < self.rows and col < self.cols: offsets = [0x00, 0x40, 0x14, 0x54] # For 16x2 LCD self._command(0x80 | (offsets[row] + col)) def print(self, text): """ Print string to LCD """ for char in text: self._data(ord(char)) def putchar(self, char): """ Print a single character to LCD """ self._data(ord(char)) def backlight_on(self): """ Turn backlight on """ self.backlight = True self._command(self.displaycontrol) # Re-send control command to update backlight status def backlight_off(self): """ Turn backlight off """ self.backlight = False self._command(self.displaycontrol) # Re-send control command to update backlight status def begin(self): """ For compatibility with other LCD libraries """ pass